The cefalexin residues in milk was rapidly and quantitatively detected by fluorescent immunochromatography assay and strip reader.MethodsThe europium nanoparticles were synthesized by RP-microemulsion technology. The Eu nanoparticles conjugated with cefalexin monoclonal antibody was used as a fluorescent label. The cefalexin-ovalbumin and goat anti-mouse IgG was respectively used as the test line and control line on the fluorescent strip. A rapid and quantitative fluorescent immunochromatography assay for detection of cefalexin residues in milk was established equipped with a strip reader. ResultsThe fluorescent immunochromatography assay had a good correlation with ELISA, with the detection limit of 0.16 ng/mL, and the IC₅₀ value was 0.6 ng/ml. The linear detection range was 0.16-5 ng/ml. The recoveries of spiked milk were between 100%-115%, and the cross-reaction rate of the antibody with 12 kinds of antibiotics including cephalosporins and penicillin was less than 0.01%.ConclusionIt was easy, rapid, and sensitive for the detection, and had the potential to be a powerful tool for screening other antibiotics residues in milk and milk products.